1. Field of the Invention
The present invention relates to a semiconductor dynamic sensor having a thin thickness structure such as a semiconductor acceleration sensor, a semiconductor pressure sensor or the like. In addition, it relates to a production method thereof.
2. Description of the Related Art
The conventional semiconductor dynamic sensor has a thin thickness structure in its interior, wherein distortion is generated by allowing a dynamic quantity such as acceleration, pressure or the like to act on this thin thickness structure, and the distortion is electrically detected according to a piezoresistance change, a capacitance change or the like.
As an effective production method for the thin thickness structure which serves as a distortion-causing portion, for example, an electrochemical etching method proposed by an official gazette of Japanese Patent Laid-open No. 62-61374 and the like is known.
Namely, the official gazette of Japanese Patent Laid-open No. 62-61374 discloses an electrochemical etching method for silicon substrates in which a P-type substrate having an N-type layer is immersed in an etching solution to oppose an electrode plate, a voltage is applied between the N-type layer and the electrode plate to perform anisotropic etching of the P-type substrate, and a distortion-causing portion and a separation groove of a semiconductor dynamic sensor are formed.
In addition, the above-mentioned official gazette discloses the fact that the etching automatically stops when it arrives at the N-type layer.